package com.company.观察者模式2;

import java.util.Observable;

public class Goods extends Observable {
    private int price;
    public Goods(int price){
        this.price=price;
    }
    public void setPrice(int price){
        int var = price - this.price;
        this.price=price;
        if (var==0){
            return;
        }
        setChanged();//声明状态已改变
        this.notifyObservers(var);
    }
}
